In JP 2005-222049 A, JP 2003-338795 A, JP 2008-026609 A and JP 2008-046467 A are disclosed devices for aligning an optical member such as a lens. In any of the devices, quantities of decentering of the optical member in directions of axes in a Cartesian coordinate system are detected and a position of the optical member is corrected in the directions of X-axis and Y-axis by respective linear actuators.
In JP 2003-338795 A, JP 2008-026609 A and JP 2008-046467 A are disclosed estimation of the quantities of decentering in the directions of the axes by wobbling in which change in power of a laser beam is detected with forward and backward displacement of the lens by a specified minute quantity, and alignment of the lens.
In JP 2008-026609 A and JP 2008-046467 A is disclosed positioning of the lens in X-Y directions by friction drive type actuators which cause a piezoelectric element to oscillate a driving shaft and which cause slide displacement of a movable member frictionally engaging on the driving shaft.